1. Field of the Invention
The present invention relates to a photosensitive composition capable of changing the property by reaction upon irradiation with actinic ray or radiation (electron beam, X-ray, EUV, UV, etc.), a compound for use in the photosensitive composition, and a pattern-forming method using the photosensitive composition. More specifically, the invention relates to a photosensitive composition for use in a manufacturing process of semiconductors, e.g., IC, the manufacture of circuit substrates such as liquid crystals, thermal heads and the like, and other photo-fabrication processes, lithographic printing plates, and acid-curable compositions, and also the invention relates to a compound for use in the photosensitive composition, and a pattern-forming method using the photosensitive composition.
2. Description of the Related Art
Chemical amplification resist compositions are pattern-forming materials capable of generating an acid at the area irradiated with radiation such as a far ultraviolet ray, changing the solubility in a developing solution of the area irradiated with the actinic radiation and the non-irradiated area by the reaction with the acid as a catalyst, and forming a pattern on a substrate.
When a KrF excimer laser is used as the exposure light source, resins having poly(hydroxystyrene) as a fundamental skeleton that is small in absorption in the region of 248 nm are mainly used, so that a high sensitivity and high resolution are secured and good pattern is formed as compared with conventionally used naphthoquinonediazide/novolak resins.
On the other hand, when a light source of further shorter wavelength, e.g., an ArF excimer laser (193 nm), is used as the exposure light source, since compounds having an aromatic group substantially show large absorption in the region of 193 nm, even the above chemical amplification resist compositions are not sufficient.
To cope with this problem, resists for an ArF excimer laser containing a resin having an alicyclic hydrocarbon structure have been developed.
Regarding an acid generator that is the main constituent of chemical amplification resists, triphenylsulfonium salts are generally known (e.g., refer to U.S. Pat. No. 6,548,221).
Further, when light sources such as electron beams, X-rays and EUV are used, exposure is carried out under vacuum, so that compounds having a low boiling point such as solvents and resist materials decomposed by high energy are volatilized to contaminate the exposure apparatus, i.e., outgassing is a serious problem. In recent years, various investigations are in progress on the reduction of outgassing, and a variety of trials are suggested, e.g., restraint of volatilization of low molecular weight compounds by forming a top coat layer (e.g., refer to EP 1,480,078), and addition of a radical trapping agent capable of inhibiting decomposition of a polymer (e.g., refer to U.S. Pat. No. 6,680,157). In connection with acid generators, some contrivances are also required on the reduction of outgassing.
Acid generators are also examined from various aspects as disclosed in JP-A-2006-78760 (The term “JP-A” as used herein refers to an “unexamined published Japanese patent application”.), JP-A-2006-171568, JP-A-2005-37887, JP-A-2005-37888, U.S. 2007/0037091 and JP-A-2006-215271.
However, acid generators are still insufficient in various points, so that a resist composition improved in sensitivity, resolution, a pattern form, and roughness is required.